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On a Class of Gibbs Sampling over Networks
Proceedings of Thirty Sixth Conference on Learning Theory, PMLR 195:5754-5780, 2023.
Abstract
We consider the sampling problem from a composite distribution whose potential (negative log density) is ∑ni=1fi(xi)+∑mj=1gj(yj)+∑ni=1∑mj=1\nicefracσij2η‖ where each of x_i and y_j is in \Rd, f_1, f_2, \ldots, f_n, g_1, g_2, \ldots, g_m are strongly convex functions, and \{\sigma_{ij}\} encodes a network structure. Building on the Gibbs sampling method, we develop an efficient sampling framework for this problem when the network is a bipartite graph. More importantly, we establish a non-asymptotic linear convergence rate for it. This work extends earlier works that involve only a graph with two nodes \cite{lee2021structured}. To the best of our knowledge, our result represents the first non-asymptotic analysis of a Gibbs sampler for structured log-concave distributions over networks.Our framework can be potentially used to sample from the distribution \propto \exp[-\sum_{i=1}^n f_i(x)-\sum_{j=1}^m g_j(x)] in a distributed manner.